The present invention relates to novel organo phosphoric acid dithioesters. More specifically this invention relates to novel organo phosphoric acid dithioesters which have excellent insecticidal activity against a wide variety of insect pests. This invention also relates to a process for the preparation of said dithioesters, and insecticides containing said dithioesters as an effective components. The term "insecticides" as used herein means both insecticides and miticides.